What's with dystopias for kids?

I recently finished reading the first book in the Divergent Trilogy, Divergent. I enjoyed it well enough, although I felt the ending removed any moral ambiguity from the plot and made things clearly good and evil.

And it got me to thinking about young adult literature and dystopias. It seems like there has been a real boom in them ever since the Hunger Games, although I've been told that the real culprit is The Giver by Lois Lowry, which I guess I now have to read.

But dystopias for kids have been around for a while. The earliest one I've been able to figure out that was meant for a young adult audience is the Tripod Trilogy by John Christopher. Civilization has been regressed to a pre-industrial level of technology, adults are all brain-washed and humanity has been subjugated by extraterrestrials.

Actually, for a series with such a clearcut enemy (I mean, we are talking about aliens invading!), it manages that moral ambiguity I look for in dystopias. While the books are about the value and importance of freedom, they also have the cynical message that humanity needs to be taken over by lobotomizing aliens to unify. Get rid of them and we're back to distrust, nationalism and war.

When you think about it, dystopias are a logical subject for young adult literature. Teenagers are crossing from being kids to adults, which is a confusing place. The world can turn out to be bigger, scarier and more serious than it has been. I'm not sure if folks ever feel in control but being a teenager creates whole new levels of not being in control. Dystopias can be a perfect metaphor for that. 

That pretty much describes the Uglies series perfectly, come to think of it.

I am sure I'll read the rest of the Divergent series and apparently The Giver as well. In them, I hope to find not just imperfect societies but examinations of humanity's imperfections.